This invention relates to new dextranases produced by Streptomyces anulatus. Two novel alkalotolerant dextranases were isolated from a single colony type that produced large clear halos in the blue dextran indicator pH 8.0. The organism was monocultured and identified by 16S rRNA sequencing as Streptomyces anulatus. Growth on dextran yielded two proteins active in hydrolyzing dextran, Dex 1 and Dex 2. Because enhanced activity lifetime after exposure to alkaline pH is important for enzymes used in detergent formulations, dextranases with these characteristics are of keen interest to the detergent industry.
Dextran is an xcex1(1xe2x86x926) glucose polymer produced mainly by the bacteria Leuconostoc mesenteroides and some Lactobacillus and Streptococcus species as an extracellular carbohydrate storage compound. Dextran is currently used in such widely divergent products as food additives, cosmetics, blood plasma expanders, and as a chromatography support matrix. Dextranases are important commercial enzymes with applications in the food, chemical, dental, and detergent industries, with fungi being the primary production host.
One major industrial application of dextranases is the reduction of sliming in sugar production. Dextran production by Leuconostoc species during processing of sugar cane causes multiple problems, including fouling of filters, reduction in yield, poor crystallization, and low quality of the final product. Additional applications include prevention of Streptococcus mutans adherence to tooth enamel, cleaning biofilms from many surfaces, including contact lenses, and modification of dextran for food additives and support applications in cosmetics and chromatography media. Potential applications of dextranases include removal of biofilms from surgical implants and food processing equipment and utensils. Dextran and related polysaccharides are known constituents of microbial biofilms, which infiltrate wooden kitchen surfaces and tools, especially cutting boards. Enzymes degrading these polysaccharides are known as (EC 3.2.1.11) xcex1-1,6-glucan 6-glucanohydrolase (xcex1-1,6 glucanase or dextranase). It is reasonable to expect that formulation of cleaning products to contain dextranase enzymes could result in enhanced product performance on wood kitchen objects.
However, for effective performance in cleaners, dextranases must be able to resist the chemical and physical requirements of use. Therefore, it is important to identify new enzymes capable of withstanding high pH (at least pH 8.0) and elevated temperature (at least 60xc2x0 C.) for a period of time consistent with exposure expected for liquid cleaner use (at least 15 min).
U.S. Pat. No. 4,466,954 discloses a dextranase-containing oral composition that comprises a dextranase enzyme and a stabilizing amount of an admixture comprising water-soluble salts of alkyl sulfates having 10, 12, 14 and 16 carbon atoms in the alkyl chain; however, the dextranase produced is from the genus Chaetomium which is a fungi.
An improved process for the production of dextranase is disclosed in U.S. Pat. No. 3,702,805, wherein said process comprises culturing a dextranase-producing microorganism selected from the genera Chaetomium, Humicola, Sporotrichum, Anixiella, Macrosporium, Streptomyces, Gibberella, Gloeosporium and Glomerella, particularly Chaetomium spirale, Chaetomium gracile, Sporotrichum asteroides, or Gibberellafujikuroi in a fermentation medium and recovering from said medium the dextranase which accumulates therein. This patent does not disclose an isolate from Streptomyces anulatus, and contains no information pertaining to the composition of matter of the dextranases.
None of the prior art references disclose the invention Dex 1 and Dex 2 alkaline tolerant dextranase species in a broth culture of Streptomyces anulatus. 
The present invention provides two novel alkalotolerant dextranases isolated during a directed screening operation in which soil, water, and biomass samples were collected from the Pawnee National Grasslands in Northeastern Colorado and screened on blue dextran plates for activity to provide an observed single colony type that consistently produced large clear halos in the blue dextran indicator, even at pH 8.0. The organism was monocultured and identified by 16S rRNA sequencing as Streptomyces anulatus. 
A further aspect of the invention is to provide growth on dextran which yields two proteins active in hydrolyzing dextran, Dex 1 and Dex 2, wherein Dex 1 has a MW of 63.3 kDa, a pH range of 5.0 to 9.5 and a temperature optimum of 40xc2x0 C. and Dex 2 has a MW of 81.8 kDa, with a pH range of 5.0 to 9.5 and a temperature optimum of 5xc2x0 C.
Another aspect of the invention is to provide enzymes that retain  greater than 50% activity from pH 5.3 to 9.3 after three hours, with 100% retention from 6.0 to 8.5 after three hours.
Yet another aspect of the invention is to provide an active protein Dex 1 characterized by sequencing
An additional aspect of the invention is to provide the active proteins Dex 1 and Dex 2 with enhanced activity lifetime after exposure to wide-ranging conditions of pH (especially excursions to alkaline pH) as enzymes for detergent formulations, as dextranases with these characteristics are of keen interest to industry.